ΔE 7.1, close: similar, with a visible difference side by side. Ink Yellow is a little darker, more saturated than Radiation Glow. They are different kinds of paint: Army Painter Radiation Glow is an opaque base/layer paint and Vallejo Ink Yellow is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Ink Yellow is a little darker, more saturated than Radiation Glow. They are different kinds of paint.
The same difference applies the other way round: Radiation Glow is a little lighter, more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Radiation Glow on the colour wheel See Ink Yellow on the colour wheel
All matches: Radiation Glow equivalents · Ink Yellow equivalents